N-bromobutanimide → (S)-tert-butyl 1-(9-bromo-5H-chromeno[3,4-c]pyridin-8-yloxy)-4-methylpentan-2-ylcarbamate

Participants

Reaction Steps

A solution of tert-butyl (1-((5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate (0.072 g, 0.181 mmol) in acetonitrile (5 mL) cooled to 0° C. and stirred for 2 min. NBS (0.029 g, 0.163 mmol) was added in single portion and the reaction mixture stirred at 0° C. for 2 h. The solvent was removed under reduced pressure and water 10 mL) was added. The product was extracted with ethyl acetate (3×15 mL). The combined organic extracts were washed with water (1×20 mL) dried over sodium sulfate and concentrated under reduced pressure. The residue was purified via preparative TLC (40% EtOAc:pet ether) to obtain (S)-tert-butyl 1-(9-bromo-5H-chromeno[3,4-c]pyridin-8-yloxy)-4-methylpentan-2-ylcarbamate (30 mg, 0.063 mmol, 35% yield). 1H NMR (400 MHz, CD3OD) δ 8.48 (d, J=5.4 Hz, 1H), 8.38 (s, 1H), 8.07 (s, 1H), 7.68 (d, J=5.4 Hz, 1H), 6.73 (s, 1H), 5.21 (s, 2H), 4.02-3.98 (m, 3H), 1.92-1.71 (m, 1H), 1.56-1.52 (m, 2H), 0.97 (t, J=6.8 Hz, 6H).

Provenance & Evidence